There are lots of excellent boutique EL-84 amps out there, but none that I've heard sound all that much like a JMI AC-30. I went down that road before (twice actually), and ended up getting a JMI - because that's the sound I wanted.

I'm not a big fan of the Korg reissues, but they will get you a lot closer to the sound of an old JMI than the boutiques. I've also read on this board recently that there might be someone out there making faithful copies of old JMIs. Good luck.